Conjugation is the creation of derived forms of a verb from one basic form. It may be affected by person, number, gender, tense, mood, voice or other language-specific factors. When, for example, we use a verb to function as the action done by a subject, most languages require conjugating the verb to reflect that meaning. (For more information on conjugation in general, see the article on grammatical conjugation.)
In Latin, there are four main patterns of conjugation composed of groups of verbs that are conjugated following similar patterns. As in other languages, Latin verbs have a passive voice and an active voice. Furthermore, there exist deponent and semi-deponent Latin verbs (verbs with a passive form but active meaning).
In a dictionary, Latin verbs are always listed with four principal parts which allow the reader to deduce the other conjugated forms of the verbs. These are:
Deponent verbs are verbs that are passive in form (that is, conjugated as though in the passive voice) but active in meaning. These verbs have only three principal parts, since the perfect tenses of ordinary passives are formed periphrastically with the perfect participle, which is formed on the same stem as the supine.
Deponent verbs use active conjugations for tenses that do not exist in the passive: the gerundive, the supine, the present and future participles and the future infinitive.
Semideponent verbs form their imperfect tenses (present, imperfect, and future) in the manner of ordinary active verbs; but their perfect tenses are built periphrastically like deponents and ordinary passives; thus semideponent verbs have a perfect active participle instead of a perfect passive participle.
Principal parts for the active voice
The first conjugation is characterized by the vowel a and can be recognized by the -āre ending of the present infinitive.
The principal parts of a first-conjugation verb follows the pattern: amō, amāre, amāvī, amātum (to love)
The second conjugation is characterized by the vowel e and can be recognized by the -eō ending of the first person present indicative and the -ēre ending of the present infinitive.
The principal parts of a second-conjugation verb follows the pattern: dēleō, dēlēre, dēlēvī, dēlētum (to destroy)
The third conjugation consists of two sub-forms sometimes referred to as the third normal (or e stem) and third special (or i stem) forms. In the normal form the first person present indicative ends in -ō. In the special or i stem form, the first person indicative ends in -iō. In both cases the present infinitive ends in -ere.
The principal parts of a normal third-conjugation verb follows the pattern: legō, legere, lēgī, lēctum (to read)
The principal parts of a special third-conjugation verb follows the pattern: capiō, capere, cēpī, captum (to capture)
The fourth conjugation is characterized by the vowel i and can be recognized by the -īre ending of the present infinitive.
The principal parts of a fourth-conjugation verb follows the pattern: audiō, audīre, audīvī, audītum (to hear)
There are also some verbs that are irregular and do not fall into one of the four categories. Some examples include:
sum, esse, fuī, -- (to be) and its compound forms
eō, īre, iī (ivī), itum (to go) and its compound forms
volō, velle, voluī, -- (to want)
nōlō, nōlle, nōluī, -- (to not want)
mālō, mālle, māluī, -- (to prefer)
ferō, ferre, tulī, lātum (to carry or wear)
Some verbs that fall under one of the four categories may follow its method of conjugation but not necessarily have the same progression of principal parts. This is especially true in the third conjugation, where there is no general pattern for the third and fourth principal parts of the verb. For example, the verb occīdō, occīdere, occīdī, occīsum (to kill) is third conjugation but has principal parts that are different from that of legō.
Conjugation radicals
The present infinitive radical is derived by dropping the -are, -ere, or -ire from the present infinitive.
The perfect indicative radical is derived by dropping the -i from the first-person singular perfect indicative:
amavi: amav-
delevi: delev-
legi: leg-
The supine radical is derived by dropping the -um from the supine:
amatum: amat-
Conjugation tables
For the most part, the four principal parts of a verb are sufficient information to form all other conjugations of the verb. The tables below show the conjugations of verbs in all four declensions and several irregular verbs.
First conjugation (-are): amo, amare, amavi, amatum (to love)
Notice that in all forms the endings are similar, 'o' or 'm' endings mean I. 's' means 'you' (in the pronouns 'suus' means 'his'; do not get confused) and the 't' endings mean he/she/it.
So:
Singular
-o/m = I, eg. sum or verbo
-s = You, eg. es or amas
-t = He, eg est or amat
Plural (note the simularities with the singular)
-mus
-tis
-nt
A few elements of conjugation, often similar to Latin conjugation, survive in English and can serve as helpful mnemonics. 'am' (I am) retains the nasal 'mmm' sound inherited from its ancestors (note: me). 'is' is remarkably similar to the Latin 'est'. Such similarities are a result of English and Latin's common descent from Indo-European.
